An athlete whirls a 6.41 kg hammer tied to the end of a 1.3 m chain in a simple horizontal circle where you should ignore any vertical deviations. The hammer moves at the rate of 1.64 rev/s. What is the centripetal acceleration of the hammer

The chain makes a circle of radius 1.3 m as it spins, so that 1 revolution of the hammer amounts to it moving a linear distance of 2π (1.3 m) = 2.6π m. Then the hammer's linear speed is

(1.64 rev/s) • (2.6π m/rev) = 4.264π m/s

and so the centripetal acceleration has magnitude

a = v²/r = (4.264π m/s)² / (1.3 m)

a ≈ 140 m/s²

at positions a, g kinetic energy is maximum.

at position d, potential energy is maximum.